Exodus 30:19-21

19Aaron and his sons shall 1wash their hands and their feet from it; 20when they enter the tent of meeting, they shall wash with water, so that they will not die; or when they approach the altar to minister, by offering up in smoke a fire sacrifice to the Lord. 21So they shall wash their hands and their feet, so that they will not die; and 2it shall be a perpetual statute for them, for 3Aaron and his 4descendants throughout their generations.”